In the practice of dentistry, a cast or a mold must be made according to the profile of the patient's teeth during the manufacturing of dentures, and then the dentures are formed according to the cast. The ingredients of the cast are generally chosen from impression materials or plaster. After adding water to these ingredients, the whole mixture is then stirred manually until it has a sticky texture for further utilization. Since the above mixture will solidify and set within a period of time, therefore, owing to the time constraints for manual stirring, the impression materials usually cannot be mixed evenly. Furthermore, the way of stirring manually is quite strenuous and will cause the mixture to form bubbles, thus causing the cast to retain air holes within which results in a rough surface. This defect will greatly affect the product quality of the denatures.
Since the stirring method for dental impression materials is basically manual, there is no specific mixer available. Therefore, in order to solve the above defect, the conventional technology has already disclosed a mixer for mixing dental impression materials (R.O.C. Patent Publication No. 274741). Such a mixer disclosed a transmission device, which mainly utilizes a plurality of planetary gears meshing with each other, thus, allowing the impression materials within the mixer to revolve around the sun gear while processing self-rotation. As a result, the impression materials can be mixed evenly under high-speed rotation while avoiding air bubbles formed within the mixture by the centrifugal force.
It is worth mentioning that in the prior art in FIG. 1 Prior Art and FIG. 2 Prior Art, a chamber 11 and a housing cup 12 of such mixer can be activated by the transmission of several gears 13, so as to perform a high-speed rotation in a reverse direction. In achieving the objective of performing high-speed rotation, such mixer mainly relies on a motor 14 to provide a rotating energy. The motor 14 is hanging on a rectangular seat 15, with each of the four corners of the seat 15 being further perpendicularly equipped with a supporting pole 16. An elastic spring 18 is connecting a fixed member 17 of the supporting pole 16 and a fixed member 19 at the top of the motor 14, so that the motor 14 and every mechanism located on top of it can be hung on the seat 15. The mixer performs anti-vibration effect through the resilient force of the elastic spring 18. However, since the above elastic spring 18 only connects the top of the motor 14 to the seat 15, when the motor 14 is operating, the bottom of the motor 14 might over vibrate because of the unconstrained bottom portion. Such a defect will eventually affect the operation stability of the motor 14 and every mechanism mounted on top.